January 2003 Regents
#4150
Highlight to reveal answers and explanations
Questions 110 Questions 1120 Questions 2130 Questions 3140 Questions 4150 
41 Which
phase change represents a decrease in entropy?

2 


42 Given the equation: 2C_{2}H_{2} (g) + 5O_{2} (g) → 4 CO_{2 }(g) + 2H_{2}O(g) How many moles of oxygen are required to react completely with 1.0 mole of C_{2} H_{2} ?

1 


43 A student intended
to make a salt solution with a concentration of 10.0 grams of solute per liter of solution. When the student’s solution was analyzed, it was found to contain 8.90 grams of solute per liter of solution. What was the percent error in the concentration of the solution?

3 


44 What is the molarity of a solution
of NaOH if 2 liters of the solution contains 4 moles of NaOH?

2 


3 
Temperature must be in Kelvin


6 According to
Reference Table J, which of these metals will react most readily with 1.0 M HCl to produce H_{2}(g)?

2  The higher up on table J  
47 The graph below represents the
heating curve of a substance that starts as a solid below its freezing point.
What is the melting point of this substance?

2 
The lower plateu
is the melting/freezing phase change. Look at teh temp. there.
The upper plateu should be longer and it represents vaporization (requires more energy), 

48 Given the unbalanced equation: __Fe_{2}O_{3} + __CO → __Fe + __CO_{2} When the equation is correctly balanced using the smallest wholenumber coefficients, what is the coefficient of CO?

3  1:3:2:3  
2  alcohol OH only  
4  Since energy is a reactant it will consume the added energy and shift right, therefore increasing the [NO_{2}]. 
Questions 110 Questions 1120 Questions 2130 Questions 3140 Questions 4150 
Back to Regents Exams 